If they are PHP files intended to be called by the command line then PHP binary should be used at
/hsphere/shared/php4/bin/php
or
/hsphere/shared/php5/bin/php
If it is intended to use them as if they were in the web browser then wget should be used, available at /usr/share/wget
i.e.
/usr/share/wget -v --delete-after http://domain.com/path/to/script.php
More instructions on how toconfigure crontabs.
For other web server configurations please contact support